Clinical Relevance Five days of at-home whitening with 10% carbamide peroxide (eight hours/day) produces a similar tooth whitening result as one in-office treatment with 25% hydrogen peroxide (one hour). SUMMARY Objective: This study evaluated the time necessary for at-home whitening (HW) to match the results of an in-office (OW) treatment, side effects and patients' preferences/perceptions. Methods: The tooth color change of 20 subjects was measured using a shade guide (BSG) and spectrophotometer (ES). Color difference was calculated: ΔE*= [(ΔL*) 2 + (Δa*ab) 2 + (Δb*ab) 2 ] 1/2 . The whitening treatments were randomly applied to the right or left maxillary anterior teeth, in-office, with 25% hydrogen peroxide or at-home, overnight, with 10% carbamide peroxide. The tooth color was evaluated at baseline, one day after OW, six days (five days after HW) and at 20 days (14 days after HW and 19 days OW). Subjects rated their tooth and soft tissue sensitivity (1–10 scale). The results were analyzed by two-way RM ANOVA/Tukey's and Mann-Whitney ( p <0.05). Results: At six days, the teeth that were treated with HW and OW presented ΔE* = 5.2 and 6.6, respectively, ΔBSG=3, and at 20 days, they presented ΔE* = 6.2 and 6.6, respectively, ΔBSG = 3. Less than 40% of the subjects experienced tooth sensitivity after OW and HW. No subjects experienced tooth and gingival sensitivity at 20 days. Seventy-four percent preferred HW over OW, 63% recommended OW and 100% recommended HW. Conclusion: While there was a subtle difference in ΔE* between HW and OW at six days, the measurement of ΔE* and ΔBSG agreed that five days of home whitening produced the same results as a single in-office treatment. The tissue and teeth sensitivity were mild and transient. Subjects preferred and would recommend HW over OW.
Clinical Relevance The marginal gap of ceramic onlays manufactured by Cerec 3D present a similar marginal gap whether the optical impression is taken intraorally using the Cerec powder or extraorally using a stone model. SUMMARY Objectives: This study evaluated the marginal gaps on several surfaces of onlays created with the Cerec 3D system using one intraoral and two extraoral optical impression methods. Methods: A human molar (#19) was mounted with its adjacent teeth on a typodont (Frasaco) and prepared for a MODL onlay. The typodont was assembled in the mannequin head in order to simulate clinical conditions. The same operator took 36 individual optical impressions using a CEREC 3D camera. For group 1 (IP), a thin layer of titanium dioxide powder (CEREC powder-VITA) was applied directly onto the surface of the preparation for imaging (n=12). For group 2 (EP), a sectional impression was taken with hydrocolloid Identic Syringable (Dux Dental), a die made with polyvinylsiloxane KwikkModel Scan (R-dental Dentalerzeugnisse GmbH) and powdered with titanium dioxide for imaging (n=12). For group 3 (ES), a sectional impression was taken with PVS and a sectional stock tray, a die fabricated in stone (Diamond die- HI-TEC Dental Products) and the die being imaged without powdering (n=12). One operator designed and machined the onlays in VitaBlocks Mark II for Cerec (VITA) using a CEREC 3D. The marginal gaps (μm) were measured with an optical microscope (50×) at 12 points, three on each surface of the MODL. The results were analyzed by two-way ANOVA/Tukey's ( p =0.05). Results: The overall mean marginal gaps (μm) for the three methods were: IP=111.6 (± 34.0); EP=161.4 (± 37.6) and ES=116.8 (± 42.3). IP and ES were equal, but both were significantly less than EP. The pooled mean marginal gaps (μm) for the occlusal = 110.5 (± 39) and lingual = 111.5 (± 30.5) surfaces were equivalent and significantly less than the distal = 136.5 (± 42.5) and mesial = 161.1 (± 43.3). Conclusion: The marginal gap of CEREC 3D onlay restorations was not different when the optical impression was taken intraorally vs extraorally using a stone cast that does not require powdering. The lingual and occlusal surfaces showed the lowest gaps.